When a business entity sells goods or services and issues an electronic uniform invoice, and subsequently both the seller and the purchaser agree to a sales return or allowance, or a purchase return or allowance, the entity shall issue, transmit, or receive the Certificate of Sales Return, Purchase Return, or Allowances via the Internet or other electronic means. The relevant files shall include the retention media file, the receipt media file, and the certification media file. The purposes of these files are as follows:
1. Retention Media File: To be retained by the seller business entity and used as an accounting voucher and for declaring deductions of output tax in accordance with the provisions of the Act.
2. Receipt Media File: To be provided to the purchaser as a receipt and, where the purchaser is a business entity, used as an accounting voucher and for declaring deductions of input tax in accordance with the provisions of the Act.
3. Certification Media File: To be transmitted by the seller business entity to the Platform for certification.
The seller business entity may download and print the Certificate of Sales Return, Purchase Return, or Allowances in the prescribed format from the retention media file to serve as an accounting voucher and for declaring deductions of output tax.  The purchaser business entity may download and print the Certificate of Sales Return, Purchase Return, or Allowances from the certification media file on the Platform, to serve as an accounting voucher and for declaring deductions of input tax.